public class Test {
    public static void main(String[] args) {
        LinkedList s1=new LinkedList();
        s1.addFirst(6);
        s1.addFirst(2);
        s1.addFirst(6);
        s1.addFirst(4);
        s1.addFirst(5);
        s1.addLast(6);
        System.out.println(s1.contains(10));
        System.out.println(s1.size());
        s1.addIndex(3,99);
        s1.removeAllKey(6);
        s1.display();
    }

}
